Positive and Negative Tone Protein Patterning on a Photobase Generating Polymer

Abstract

This study investigates the use of a copolymer containing O-acryloyl acetophenone oxime (AAPO) and a 4-acryloyloxybenzophenone (ABP) sensitizer as a platform suitable for the patterning of proteins. While low dose UV exposure (312 nm) of the acyloxyimino component photogenerates pendant amine groups at the polymer surface, rendering it protein repelling, the laser ablation method (337 nm) creates hydrophobic features on which proteins adsorb preferentially. These patterning methods produce negative and positive tone protein features, respectively. A critical factor that ensures the quality of the protein patterning is the unusual photodarkening effect for the exposure wavelengths, which concentrates the photoinduced physicochemistry at the very surface of the polymer. The versatility of the proposed patterning methods makes AAPO−ABP an interesting candidate for the patterning of proteins for biochip fabrication.